LTC4065-4.4_15 Datasheet, PDF (1/16 Pages) Linear Technology – Standalone 750mA Li-Ion Battery Charger

LTC4065-4.4
Standalone 750mA Li-Ion
Battery Charger in 2 × 2 DFN
FEATURES
■ _{Complete Linear Charger in 2mm × 2mm DFN}
Package
■ _{C/10 Charge Current Detection Output}
■ _{Timer Termination}
■ _{Charge Current Programmable Up to 750mA with}
5% Accuracy
■ _{No External MOSFET, Sense Resistor or Blocking}
Diode Required
■ _{Preset 4.4V Float Voltage with 0.6% Accuracy}
■ _{Constant-Current/Constant-Voltage Operation with}
Thermal Feedback to Maximize Charging Rate
Without Risk of Overheating
■ _{Charge Current Monitor Output for Gas Gauging}
■ _{Automatic Recharge}
■ _{Charges Single-cell Li-Ion Batteries Directly from}
USB Port
■ _{20µA Supply Current in Shutdown Mode}
■ _{Soft-Start Limits Inrush Current}
■ _{Tiny 6-Lead (2mm × 2mm) DFN Package}
U
APPLICATIO S
■ _{Wireless PDAs}
■ _{Cellular Phones}
■ _{Portable Electronics}
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners. Protected by U.S. Patents,
including 6522118, 6700364.
DESCRIPTIO
The LTC^®4065-4.4 is a complete constant-current/con-
stant-voltage linear charger for high capacity single-cell
lithium-ion batteries with a 4.4V float voltage. Its 2mm ×
2mm DFN package and low external component count
make the LTC4065-4.4 especially well-suited for portable
applications. Furthermore, LTC4065-4.4 is specifically
designed to work within USB power specifications.
The CHRG pin indicates when charge current has dropped
to ten percent of its programmed value (C/10). An internal
timer terminates charging according to battery manufac-
turer specifications.
No external sense resistor or blocking diode is required due
to the internal MOSFET architecture. Thermal feedback regu-
lates charge current to limit the die temperature during high
power operation or high ambient temperature conditions.
When the input supply (wall adapter or USB supply) is
removed, the LTC4065-4.4 automatically enters a low cur-
rent state, dropping battery drain current to less than
1µA. With power applied, LTC4065-4.4 can be put into shut-
down mode, reducing the supply current to less than 20µA.
The full-featured LTC4065-4.4 also includes automatic
recharge, low-battery charge conditioning (trickle charg-
ing) and soft-start (to limit inrush current).
The LTC4065-4.4 is available in a tiny 6-lead, low profile
(0.75mm) 2mm × 2mm DFN package.
TYPICAL APPLICATIO
Standalone Li-Ion Battery Charger
V_IN
4.5V TO
5.5V
R1
510Ω
C1
1µF
V_CC BAT
LTC4065-4.4
CHRG PROG
EN GND
500mA
+ ^4.4V
Li-Ion
R3 ^BATTERY*
2k
4065 TA01
*E.G. SANYO BATTERIES: UF553436T OR UF553450T
Complete Charge Cycle (1100mAh Battery)
550
500 ^{CONSTANT-CURRENT}
450
400
4.5
4.4
CONSTANT-
VOLTAGE
4.3
4.2
350
4.1
300
4.0
250
CHRG
3.9
200
TRANSITION _3.8
150
100
50
0
0
3.7
CHARGE
3.6
V_CC = 5V
TERMINATION
3.5
R_PROG = 2K
3.4
0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
TIME (HOURS)
4065 TA01b
406544f
1